Sampling device



United States Patent 3,123,142 SAh IPLLQG DEVICE Tom W. Quinn and Paul P. Wittmer, Ponea City, Okla, assignors to Continental Oil Company, Ponca City, Okla, a corporation oi Delaware Filed Mar. 3, 1961, Ser. No. 93,137 1 Claim. (Cl. 166-469) This invention relates to the procurement of samples within deep well bores. More particularly it relates to new and useful improvements in devices for obtaining true samples under pressure conditions existing at the level where the sample is taken by means of a sampling device which is lowered into the well bore from the surface and then after the sample is taken, the device is brought to the surface where the sample can be studied. This application is a continuation-in-part of our copending application entitled Sampling Device, Serial No. 849,878, filed October 30, 1959, now abandoned.

In recent years the petroleum industry has come to a full realization of the importance of obtaining accurate data regarding hydrocarbon-bearing reservoirs. The determination, interpretation, and application of these data are commonly known by the broad term, reservoir engineering. The solution of reservoir problems requires an accurate knowledge of the reservoir fluid properties, which are especially useful in predicting the behavior of the fluid in a hydrocarbon-bearing reservoir during the productive life of the reservoir. It is noted that hydrocarbon oil and gas produced at the surface of the ground has an entirely different set of physical characteristics at atmospheric pressure and temperature than the same oil and gas has at reservoir pressures and temperatures. Hence, it is very desirable to obtain fluid samples which are truly representative of the actual fluid as it exists in the reservoir at the reservoir pressure and temperature conditions.

Heretor'ore it has been difiicult to obtain samples which actually represent subsurface mixtures of oil and gas because the oil contained in such samples have been intermingled with extraneous gas, i.e., gas which either was in solution originally or was liberated from solution at some lower pressure and later became mixed with the original sample, and/ or oil from which gas has been liberated at lower pressures at higher depths in the well bore either of which will change the composition or properties of the original sample. Furthermore, in the sampling devices heretofore available, there is a tendency for extraneous gases and/or oils to be entrapped in the device as it descends in the well bore. These entrapped gases and/ or oils of course become intermingled with the well bore sample which is subsequently obtained.

It is therefore a principal object of the present invention to provide a sampling device whereby the disadvantages of the prior art devices are obviated. It is another object of this invention to provide a sampling device whereby inaccuracies due to entrapped gases or oils may be eliminated. Another object of our invention is to provide a sampling device which is of small radial dimensions and light in weight and yet capable of effectively obtaining samples and withstanding the pressures existing at the level of the sample being taken. Other objects and advantages of the invention will become apparent to persons skilled in the art by reference to the following description and annexed drawings.

Broadly, this invention is an improved apparatus for obtaining true samples of fluids from a subterranean well bore at the point where the particular fluid actually enters the well bore. This device comprises an apparatus wherein fluids normally entrapped during the assembling and lowering operations are purged therefrom by flowing well bore fluids through the apparatus during the lowering operation until the desired depth is reached, whereupon the sample is affirmatively withdrawn into the apparatus by means of a piston and cylinder arrangement so that the apparatus, and thusly the sample, contains no extraneous gas or liquids, thereby providing accurate, uncontaminated samples normally unobtainable by apparatus known in the art. Other objects and advantages will be apparent from the following description taken in connection with the accompanying drawings. It is to be understood, however, that the drawings are for the purpose of illustration and description only and are not in tended as a definition of the limits of the invention.

In the drawings:

FEGURE 1 is a vertical sectional view of the assembled device as it appears while being lowered through the well bore but prior to the sampling operation;

FIGURE 2 is a horizontal sectional view on line AA' of FiGURE 1;

FIGURE 3 is a horizontal sectional view on line B-B of FEGURE 1; and

FIGURE 4 is a vertical sectional view of the device subsequent to the sampling operation.

Referring to the drawings in detail, and particularly FIGURES 1, 2 and 3, the sampling device ill generally comprises a housing member 11 of an elongated tubular nature threadably adapted to receive a piston retaining means 12 and a first plug means 13 in the upper end and a second plug means 1 2 in the lower end thereof. The first plug means and the piston retaining means have a bore 15 therethrough and said plug means has a passage 16 extending longitudinally and adapted to allow the passage of fluids and a wire line 17 therethrough, a plurality of ports 18 extending laterally, all of which communicate with the zone adjacent the sampling device. The second plug means has a bore 19 adapted to allow the passage of fluid therethrough, a plurality of internally threaded bores 29 and passages 21 adapted to receive a plurality of spring means 22 which are fixed therein by a plurality of set screws 23.

The housing member 11 contains a plurality of lateral ports 24 in the end adjacent the second plug means providing communication between the interior of the housing and the zone adjacent the device, a plurality of longitudinal grooves 25 above said ports 24, and has a shoulder 26 adapted to retain a flmged collar member 27, having an axially disposed aperture 28 and a plurality 'of lateral ports 46 communicating with ports 2-4, from longitudinal movement. The po nts 46 extend through the collar member and there is a sealing ring 29 circumferentially disposed about said collar adjacent housing 11 and above ports 24. A ball valve 3%? having a diameter greater than aperture 28 of collar 27 is arranged above said collar adapted to be seated in a valve seat 37 and attached to a rod 31 extending through said collar and having a spring 32 mounted about said rod at the lower end by a spring retaining means 33 and at the upper end by said collar to form a spring loaded ball valve mechanism. The collar 27 has a plurality of fingers 34 having beveled heads and being of a spring structure capable of movement under sufficient stress.

The upper portion of housing 11 forms a chamber 35 to contain a flanged piston 36 of spool-like structure having an upper flange 37 containing a plurality of apertures 38 and adapted to receive an eye-bolt 39 through which wire line it! is afiixed, and a lower flange 40 having a sealing ring 41 circumferentialiy disposed adjacent said housing. The lower end or head 42 of piston 56 has a depending finger 44 and an upwardly tapered recess inwardly of the finger with an aperture 43 at the upper end of the recess communicating with the groove 45 on the exterior of the piston. The head also has a circumferential groove 45 adapted to receive fingers 34- which retain the piston in the lower portion of chamber 35 until stress is applied against said fingers by pull on wire line 17.

In FEGURE 4 the parts and reference numerals applied thereto are the same. This view is presented to illustrate the position of the various parts after the sample has been taken, particularly piston 36, ball valve 3% and rod 31 and the chamber 35 containing a sample therein. he ball valve is seated with the rod being centered again upon removal of finger 4 and the fingers 34 are in the relaxed position with the beveled heads being in position :for resetting for a subsequent operation.

in operation the sampling device is assembled at the surface in the manner set forth in FIGURES 13 with piston 36 in the lower portion of chamber 35 whereby the finger 4d ofisets ball valve 3t and rod 31 causing increased tension on spring '32 whereby aperture 28 of collar 27 is maintained in an open position. The device is placed in the well bore and lowered by wire line 17, and a portion of the well fluids encountered flow into bore 19, by spring 32, etc., through aperture 28 where they are joined by other fluids entering ports 24-, around ball valve 3%) into chamber 35. These fluids continue to flow around fingers and aperture 43 of head 42 into contact with the lower flange 4:; having sealing ring 41, thereafter around the lower flange through grooves 25, through apertures 38 or" upper flange 37 into the upper of chamber 35, and subsequently through bore 15, passage 16 and ports 13 into the well bore again.

After the device has been lowered to the desired depth, it is raised until spring means 22 engage in a tubing joint or the like and become seated so upward movement is temporarily prevented. At this point the fluids in the apjparatus are those of the formation which the device is immediately adjacent, except perhaps in the case of an extremely thin formation whereby there could be fluids from the formation above in the upper part of chamber 35. There are, however, no fluids, and particularly no gases, entrapped in the device during assembling or lowering because all of the passages are inherentry purged by the above-described fluid flow. The lack of entrapment is due to the construction of the device, that is, the passages, apertures and ports, which makes it impossible for fluids to be trapped due to the lack of any extensive system of intricate passageways, etc. The sealing system prevents the accumulation of fluids in any of the joints of the apparatus which can tmder the pressures involved provide undesirable storage for great quantities of gas capable of preventing accuracy in the sample. At the time of positioning the device, the chamber 35 beneath the piston contains only the fluids from the adjacent formation to be sampled, particularly all contaminating fluids have been exhausted from the head through aperture 43, as do ports 24, bore 35 and grooves 25.

The device being in position, the wire line is then raised sufliciently that the stress overcomes the fingers 34 and piston 36 is released to be raised through chamber 35 until the eye-bolt and wire line extend into bore as illustrated in FIGURE As the piston is raised, the housing being temporarily anchored, the finger 44 is removed from communication with ball valve 3% which immediately becomes subject to the effect of spring 32. The ball valve does not become seated in aperture 28, however, because the force or suction exerted by the Withdrawal or" the piston to its raised position is greater than the force of spring 32, so the fluid sample from the adjacent formation is brought into the chamber through ports 24 and partially through bore 19. As the piston is raised, to lower flange 4'13 and sealing ring 41 clear all gas bubbles and dead oil from within the chamber 35 and particularly that deposited on the interior walls of housing 11 which are not ordinarily moved merely by flowing fluids, unless the flOW is turbulent as in grooves 25. Immediately upon the piston being raised until the piston abuts the piston retaining means 12, the withdrawal of the sample is complete and, since there is no further force being applied to ball valve 39 after this flow is terminated, the sprin 3'2 acting through rod 31 causes the ball valve to be seated in aperture 28. FIGURE 4 illustrates the position of the critical parts but it particularly points out the chamber 35 in a completely sealed condition with a sample therein.

The device is then lifted by the wire line with such force as is necessary to overcome springs 22 and removed from the well bore at the surface. The sample having been obtained, there remains only the removal which can be accomplished by several procedures known in the art, one of which is described below for completeness. The plug i4, rod 3!, spring 32 and retaining means 33 are removed and a conventional adapter inserted into aperttu'e 23 which seals ports 24 and furnishes a connection for removal of the sample. This adapter is then filled with mercury and thereafter the plug 13, wire line 17 and eye-bolt 39 are removed. The bore 15 is filled with mercury and pressure applied thereon to displace piston 36 through chamber 35 whereby the sample is discharged 7 through the adapter previously inserted in aperture 28 into a suitable container for subsequent analysis. As the piston is displaced downwardly in chamber 35, it contacts the beveled heads of fingers 34 which are again moved into groove 45 in order that the device is then prepared for further use upon replacing the parts removed for purposes of withdrawing the sample from the device.

While a particular embodiment of the invention has been described, it will be understood that the invention is not limited thereto, since many modifications may be made, and it is contemplated to cover by the appended claim any such modifications which fall within the true spirit and scope of the invention.

The invention having been thus described, What is claimed and desired to be secured by Letters Patent is:

An apparatus for sampling fluids in a subterranean well containing a tubular string with recesses therein comprising:

(a) an enclosed tubular housing member having an upper and lower end with first and second .plug means therein respectively,

(1) said first plug having an interior bore axially extending partially therethrough in communication with a passage axially extending through the upper end above said bore and a plurality of lateral ports communicating with the bore therein,

(2) said second plug having an interior bore axially extending therethrough adapted to receive a spring and retaining means therefor,

(3) said tubular housing member having a plurality of longitudinal grooves internally disposed intermediate of said upper and lower ends and a plurality of lateral ports disposed intermediate of said grooves and lower end;

(b) a flanged collar member sealably mounted within said tubular housing member adjacent the lower end thereof,

(13 said flanged collar member having a plurality of lateral ports communicating with an aperture centrally disposed therein and the lateral ports of said tubular housing member,

(2) said flanged collar having a valve seat about the upper portion of said aperture;

(0} a piston slidably and sealably mounted in said tubular housing member intermediate of the upper end thereof and said flanged collar member,

'( i) said piston having a flange about the end with a plurality of apertures extending vertically through the flange communicating with the upper end of said tubular housing member,

(2) said piston having a connecting means adapted to receive a Wire line extending from the upper end of said tubular housing member,

(3) said piston having a head with a finger depending therefrom and an upwardly tapered recess inwardly of said finger with an aperture at the upper end of the recess communicating with the longitudinal grooves of said tubular housing member;

(at) a ball valve disposed above the aperture of said flanged collar member engageable with the finger of said piston and mounted on a rod,

(1) said rod being biased by a spring disposed between said flanged collar member and a spring retaining means uring said ball valve into sealing engagement with the valve seat of said flanged collar member;

(e) a plurality of fingers mounted on said flanged collar member adapted to releasably engage said piston adjacent said flanged collar member;

(1) a wire line extending from the connecting means of said piston and extending through the bore and passage in said first plug means of the upper end of said tubular housing member; and

(g) a plurality of spring means mounted on said second plug means of the lower end of said tubular housing member adapted to engage the tubular string within the Well,

whereby the apparatus is lowered into the well to the desired depth with passage of the well fluids through said apparatus and raised by the wire line until the spring means of the lower end of said tubular housing member engage the interior of said well whereafter tension on the wire line is increased to withdraw said piston and concurrently fluids from the well into the upper end of said tubular housing member and thereafter removing said apparatus from the well.

References Cited in the file of this patent UNITED STATES PATENTS 1,804,700 Maxwell May 12, 1931 2,862,561 Teubner Dec. 2, 1958 2,879,850 Exline Mar. 3 1, 1959 2,998,333 Schwab Oct. 13, 1959 

